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Sökning: WFRF:(Lundqvist Per Professor)

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1.
  • Bixby, H., et al. (författare)
  • Rising rural body-mass index is the main driver of the global obesity epidemic in adults
  • 2019
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 569:7755, s. 260-4
  • Tidskriftsartikel (refereegranskat)abstract
    • Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.
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2.
  • Mölleryd, Bengt A, 1947- (författare)
  • Governance of innovation - deploying an architectural framework for innovation of technological systems for energy, security and defence
  • 2018
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Governance of innovation – deploying an architectural framework for innovation of technological systems for energy, security and defence Innovation has a great deal of attraction but is associated with serious uncertainties and downsides. It is potentially beneficial for growth, sector and industrial development and competitiveness. Innovation brings hope of solving societal challenges, such as climate change and environment protection, and could help secure a supply of energy. Furthermore, it improves resilience and strengthens security and defence.The downside of innovations of some magnitude concern severe transitions and disruptions. Digitisation, with associated net technologies, is an illustrative example of an innovation that creates new services, competitiveness and other benefits which is enormously positive and attractive, while simultaneously dismantles and destroys existing systems, firms and branches, and whole sectors and practices.The thesis deals with promoting innovations at large but specifically systemic, defined as a value-adding (to customers and users) set or convergence of new products/services from technological systems in processes which emerge by evolutionary association and integration of systems transforming businesses, industries and sectors (with disruptions as consequence). Innovations are distinguished by certain structural properties namely systemicitiness. The systemicitiness of innovations suggests a distinct architectural framework that determines the structure of innovations. The purpose of the proposal for an architectural framework for innovation is guidance to governance of innovation. Platform based ecosystems exemplifies an emulation of systemic innovation that aligns with the proposed framework. The framework is distilled from cases, events, patterns, landscapes and models of innovation in the literature, connected with examination of systemicitiness and governance approaches to innovation and innovation processes. The architectural framework is conjected as compatible and complementary to common policies and instruments for innovation and innovation processes as holistic systems engineering, standards and protocols (e.g. ISO/IEC 15288:2015, ISO/IEC 42010:2011, NISP).
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3.
  • Lundqvist, Eva, 1985- (författare)
  • Distal radius fractures AO type C : A clinical and radiographic investigation
  • 2022
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The function of the hand is of substantial importance, and injuries have an impact on daily life. Distal radius fracture (DRF) is the most common fracture among adults. The annual incidence is 26 per 10,000 inhabitants, and the incidence is increasing because of an aging population. There has been a shift from conservative and other operative treatments, toward volar plate fixation to restore the anatomy and improve results. Operative treatment is often considered for displaced and unstable fractures. The optimal choice of treatment and fixation is still debated. The aim of this thesis was to study results after internal fixation of DRF AO type C.Study I (retrospective study, n=74) assessed outcomes after combined plating (CP) of DRFs AO type C, with 1-year follow-up. CP restored the anatomy and achieved a good functional outcome. The radiographic outcome did not correspond to the clinical or functional outcome.Study II (prospective study, n=97) assessed the prevalence of post-traumatic arthritis (PA) following CP of DRFs AO type C. CP yielded a good clinical outcome 7 years postoperatively and the prevalence of PA was low (29%). The presence of PA did not correlate with fracture group, radio-graphic, clinical, or functional outcome. Study III (randomized controlled trial, n=147) assessed the radiographic and clinical outcome following surgical treatment of DRFs AO type C, comparing volar plating (VP) with CP. Fixation with VP yieldedthe same radiographic and functional results as CP, but with a lower frequency of complications in the VP group.Study IV (prospective pilot study, n=10) assessed fragment migration with CTMA (CT-based micromotion analysis) after osteosynthesis with VP after DRF AO type C. The CTMA technique indicated that variable angle volar locking plate fixation can yield and maintain a stable reduction of the fracture fragments. CT volume registration could be a valuable tool in the detailed assessment of fracture fragment migration following VP fixation of DRFs. 
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4.
  • Poppi, Stefano, 1982- (författare)
  • Solar heat pump systems for heating applications : Analysis of system performance and possible solutions for improving system performance
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Solar heat pump systems (SHPs) are systems that combine solar energy and heat pumps. SHPs have been investigated for several decades and have been proven to increase the share of renewable energy and reduce electric energy demand in residential heating applications. Many solar thermal heat pump systems have become market-available in recent years; however these systems are still not widely employed in the residential sector. This is due mainly to the high initial costs (investment and installation costs) of solar thermal heat pump systems, which limits their cost-effectiveness. Enhancing cost-effectiveness of solar thermal heat pump systems is necessary for a more effective and broader market penetration.In this thesis, solar thermal and photovoltaic systems combined with heat pumps for heating applications are treated. The overall aims of the thesis are to: 1) investigate techno-economics of SHPs and 2) investigate possible solutions for improving system performance of a reference solar thermal and heat pump system for residential heating applications.In the first part of the thesis, the influence of climatic boundary conditions on economic performance of SHPs has been investigated by means of: a) an economic comparison of SHPs found in the relevant literature and b) system simulations of the reference solar thermal heat pump system.In the second part of the thesis, potential solutions for improving system performance of the reference solar thermal heat pump system with limited change in system’ costs are investigated. A systematic approach was used for investigating cost-effectiveness of the system improvements in the reference system.Based on results of the cost-effectiveness analysis, some of the investigated system improvements were chosen for being included in the design of a novel solar thermal and air source heat pump system concept. The novel system was designed for a house standard with relatively high operating temperatures (55°C/45°C) in the space heating distribution system and for high space heating demand (123 kWh/m2·year). Finally, the thesis ends with a cost-effectiveness analysis of the novel system.
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5.
  • Anund Vogel, Jonas, 1981- (författare)
  • Incentivising Innovation in the Swedish Construction Industry
  • 2020
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Almost 40 percent of global final energy use and CO2 emissions are connected to buildings and building-related activities; it is therefore important to incentivise the design and construction of resource-efficient buildings. Unfortunately, energy demand and associated emissions in the sector continue to grow. Such incentives will help achieve energy and environmental targets, reduce costs, and make smart and sustainable buildings and cities possible at a larger scale. Because novel technologies carry risks alongside their advantages, developers, contractors and consultants must have incentives to reduce and share those risks in a rational way if we are to meet the crucial long-term societal goals of reduced use of resources and emissions. I hypothesise that there are legal and institutional frameworks (rules, building codes, regulations, standard contracts, etc.) that result in weak or negative incentives for construction industry actors to invest in, propose, and install resource-efficient technologies. If the hypothesis holds true, then the goal is to identify ways to better incentivise construction industry actors to fully engage in the design and construction of smart and sustainable buildings. To tackle this, four studies were carried out using a mixed-method approach. Paper 1 identifies 38 barriers to energy efficiency in Swedish multifamily buildings. The next study (Paper 2) develops a categorisation framework in order to understand where to engage to overcome or bypass barriers to energy efficiency. Paper 3 and 4 are devoted to analysing two sets of barriers and propose possible solutions to overcome or avoid them: (1) how the current legal framework guiding start and operation of housing co-operatives (mainly the Co-operative Act) influences incentives for engaging in resource-efficient construction, and (2) how the legal instrument for collaboration between developers and consultants incentivises resource-efficient construction. In this case, the contract under investigation is the General Conditions of Contract for Consulting Agreements for Architectural and Engineering Assignments (ABK 09)”. Changes to these two sets of legal and institutional frameworks could have a significant impact on how buildings are designed, produced and used. The changes proposed could incentivise construction industry actors to fully pursue the creation of smart, sustainable buildings that deliver services to users and reduce negative environmental impacts stemming from both the building construction and operation phases.
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6.
  • Bäcklund, Katarina, 1982- (författare)
  • Human-Centric Operations of Smarter Higher Educational Buildings in Sweden
  • 2024
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This PhD thesis is based on four articles, each focused on distinct research areas: building occupants, smarter higher educational buildings, smart building systems and the digital transformation of real estate organizations. Rather than concentrating on one specific research area, the objective was to provide a comprehensive view of the broader system and delve into these four key research areas. Thus, they are all interdependent and require equal attention to facilitate the digital transformation within the commercial real estate industry. This transformation aims to create a more climate neutral built environment while ensuring good quality indoor comfort. The findings reveal a paradox within smart building systems, where building occupants are often treated as passive agents and interactions are intentionally reduced. However, it can be argued that some interactions will be beneficial, as building occupants considered as active agents could contribute to a more sustainable building operation. This study also concludes that current smart buildings are not yet smart enough and that all data is not smart data. Furthermore, the investigation into what constitutes a smart building has led to the identification of key features of smarter higher educational buildings. Finally, the concluding part of this study delved into the organizational challenges associated with digital transformation, proposing potential solutions to enhance innovation processes. Based on these findings, a framework for human-centric digital transformation was proposed.   
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7.
  • Choque Campero, Luis Antonio, 1986- (författare)
  • The Stirling engine as a part of a hybrid power system : a study of applications in rural areas of Bolivia
  • 2021
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Rural electrification in developing countries has become one of the greatest challenges for achieving global access to electricity—one of the United Nation’s sustainable development goals. Governments, international entities and private companies are tasked with improving the quality of life for people and reducing environmentally harmful emissions. Bolivia’s political agenda has been working in coordination with international cooperation organizations, and it has achieved great improvements in access to electricity in recent years. Different strategies and technologies have been used in the various climate scenarios that span Bolivia’s territory. Although more Bolivians have access to electricity than 10 years ago, insufficient knowledge, training, and follow-up from local and national actors (such as power producers, power distributors, and electricity service providers) prevent these solutions from operating as expected.This study explores the integration of a Stirling engine into a small power production system for use in remote rural areas. The Stirling engine is a well-known technology that can use local fuels to generate power and heat. Here two different hybrid power systems in three case studies are compared: the first system is using photovoltaic (PV) panels, batteries, and diesel engines and the second is using PV panels, batteries, and Stirling engines. In a sustainability analysis the environmental effects, economy, and performances—efficiency and reliability—of the two systems are compared. In addition, the study discusses the maintenance of the Stirling engine in Bolivia rural conditions.The study began by gathering data from 17 households in different communities, which had just obtained access to electricity. These communities are characterized by different environmental and climate conditions, which allows us to better understand how the systems operate under Bolivia’s varying climate and to consider the state of its economy and technical capacity. With the help of GIS (Geographical Information System) maps, three Bolivian communities were selected: Tirina, Tablani, and El Carmen. Six hybrid power system were simulated for these communities, two dynamic models per community. The comparison between the two systems shows that Stirling engine hybrid power system produces at least 7 Tons per year less CO2 emissions than the Diesel hybrid power system per community. The financial analysis used the levelized cost of electricity (LCOE) to show the two systems’ cost per kilowatt-hour (in USD). The LCOE of the Stirling system is higher than the diesel engine in the three communities. The net present value was calculated to reflect the costs of the initial investment, as well as maintenance, spare parts, and so on, over the duration of the study. Finally, performance of the two systems was analyzed through a simulated one-day dynamic test of both systems in the three communities. The two systems responded without problem to the communities’ power demands. These power demands have peaks between about 5 kW and 7 kW. 
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8.
  • Grozdek, Marino, 1977- (författare)
  • Load Shifting and Storage of Cooling Energy through Ice Bank or Ice Slurry Systems : modelling and experimental analysis
  • 2009
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Ice based Cool Thermal Energy Storage (CTES) systems have attracted much attention during last few decades. The reasons are mainly of economical and environmental nature. Compared to conventional refrigeration and air-conditioning systems without cool thermal energy storage, implementation of CTES will increase environmental standards and overall efficiency of the energy systems as it contributes to the phase-out of synthetic refrigerants and reduces peak loads in electricity grids. For the application of a cool thermal energy storages in refrigeration installations and HVAC systems in industry and building sector, it is necessary to have appropriate design tools in order to sufficiently accurate predict their performance. In this thesis theoretical and experimental investigations of two ice based cool thermal energy storage systems, namely static, indirect, external melt, ice-on-coil, i.e. ice bank system and dynamic, ice slurry cool thermal energy storage system are carried out. An ice bank storage technology for cooling purposes is known for a long time. The main drawbacks which are hindering its wider use are the system complexity, high first costs, system efficiency which is highly dependant on design, control and monitoring of the system, etc. On the other hand, ice slurry technology was not well studied until recently, while in the current scientific literature there are still differences between results and conclusions reported by different investigators. The aim of the present thesis is to extend the knowledge in the field of ice based CTES systems, thereby contributing in the development and wider utilization of those systems. In the first part of the thesis a computer application, named “BankaLeda” is presented. It enables simulation of an ice bank system performance. In order to verify developed simulation model an experimental evaluation has been performed. Field measurements have been conducted on a two module silo which was installed as a part of the refrigeration system in dairy and cheese factory “Antun Bohnec” in the city of Ludbreg in Croatia. Experimental findings were compared to the simulation model. The software „BankaLeda“ presents a strong optimization tool for designers and engineers in the field by providing a high degree of freedom in defining particular system design and operating parameters. It offers a basis for assessment and testing of a new energy efficient system arrangements and measures. Besides it will give decisionmakers the ability to test potential solutions in the process of CTES system design. In the second part of the thesis ice slurry pressure drop and heat transfer in horizontal straight tubes have been experimentally investigated. In particular a mixture of 10.3 % of ethanol and water with an initial freezing point of -4.4 °C was considered. It was found that the behaviour of ice slurry flow is changing with time and that ice slurry pressure drop is generally higher than for single phase flow. However for ice concentrations of 15 % and higher, for certain velocities ice slurry pressure drop is found to be of a similar value as for single phase fluid. Moreover, if ice slurry is to be used as a energy transport media it is recommended to keep the ice mass fraction at a level of 20 %. With tube geometry and thermophysical properties of a carrier fluid the heat transfer of ice slurry is generally a function of ice mass fraction and velocity. The imposed heat flux has no or has just minor influence on the heat transfer coefficient. Up to ice mass fraction between 10-15 % the mean heat transfer coefficient shows only slight (laminar flow) or no increase (turbulent flow) in comparison to single phase flow. Beyond that ice mass fraction the heat transfer coefficient is increasing significantly. The test data for pressure drop and heat transfer in laminar and turbulent regime was compared to several correlations from the literature. A new correlations for ice slurry pressure drop and heat transfer in the laminar flow regime, for 10.3 % ethanol and water mixture, were derived based on the present experimental data. The correlation for pressure drop predicts 82 % of the experimental data with ±15 % accuracy, while the correlation for heat transfer predicts 75 % of the data with the same accuracy. In order to investigate advantages and disadvantages of a dynamic, ice slurry system over a static, indirect, external melt, ice-on-coil CTES system and to assess their differences from economical aspects, a theoretical simulation model of an ice slurry CTES have been developed. It was found that the ice slurry based CTES systems posses higher economic and energy saving potential than static type systems. In the best case scenario the total energy consumption of dynamic CTES system was found to be approximately 25 % lower than for a static CTES system.
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9.
  • Lundqvist, Carina (författare)
  • Human intraepithelial lymphocytes : a comparative study of phenotype, morphology, and functional properties of intraepithelial lymphocytes in gut and oral mucosa
  • 1995
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Human intraepithelial lymphocytes (IEL) constitute a unique cell population situated in the first line of defense of the alimentary tract. Here they are continuously exposed to a massive antigenic load of high complexity. However, different conditions prevail along the alimentary tract. In small intestine food antigens dominate whereas bacterial antigens are abundant in large intestine. The oral cavity is exposed to an enormous variety of antigens from the microflora as well as food constituents. The abundance and selective localization of lymphocytes in the surface epithelium of these challenged tissues implicate important roles for IEL in immune protection.IEL in normal human jejunum, ileum and colon as well as in normal and chronically inflamed gingiva were studied in situ and after isolation, with regard to phenotype, ultrastructure, cytokine mRNA expression and response to T-cell mitogens. Furthermore, an isolation technique was developed which yielded highly purified, functionally active IEL and enterocytes from the same sample.Intestinal IEL were situated in the basal part of the epithelium, often in small clusters and in close contact with adjacent lymphocytes and epithelial cells. They had an irregular shape with long processes and some had pseudopodium-like extensions penetrating the basement membrane. This indicates cell co-operation within the epithelium, as well as transmigration of IEL to underlying tissues. Freshly isolated IEL expressed several cytokines (IL-1β, IL-8, IL-2, TNF-α and IFN-γ) and in vitro activation induced expression of IL-2, IL-10, IFN-γ, TNF-α, TNF-β and TGF-β1, suggesting that IEL are involved in cell mediated cytotoxicity and suppressor cell activities.γδ T cells showed preferential homing to the epithelium both in gingiva and in intestine. They constituted the major lymphocyte population in normal gingiva and on average 30% of IEL at all levels of the intestine. Gingival as well as intestinal γδ IEL showed preferential usage of Vδ1Vγ8, suggesting common reactivity patterns along the alimentary tract. Intestinal γδ IEL and γδ IEL in normal gingiva were CD4-CD8-. In contrast, γδ IEL in chronically inflamed gingiva were predominantly CD8+ and showed induced expression of CD45RO. This indicates that γδ IEL participate in anti-bacterial immune responses in mucosa. Intestinal and gingival γδ IEL displayed ultrastructural features of cytolytic effector cells, e.g. electron-dense cytoplasmic granules and multivesicular bodies. They also expressed cytokines indicative of cell mediated-cytolytic effector functions. γδ IEL from inflamed gingiva expressed IFN-γ, TNF-α, TGF-β1 and IL-6 mRNA while intestinal γδ IEL expressed IL-2, IFN-γ and TNF-α.Intraepithelial αβ T cells were rare in gingiva while they constituted the major population of intestinal IEL. The phenotype of αβ IEL varied at different levels of the intestine. Thus, CD8+αβ IEL dominated in jejunum while cells with the unusual T-cell phenotype, CD4-CD8- TCR αβ+, constituted a major population of colonic IEL. CD4+ αβ IEL were equally represented, as a minor population, at all three levels of the gut. Intestinal αβ IEL had the same cytokine profile as γδ IEL. Taken together, these data suggest that αβ IEL are involved in immunoregulatory responses to luminal antigens.IEL with thymocyte-like phenotyped (CD2+TCR/CD3-, CD1+TCR/CD3-, CD1+TCRαβ+ and CD1+TCRγδ+) were present in jejunal epithelium. Furthermore, recombination activating gene-1 (RAG-1) mRNA was expressed in CD2+TCR/CD3- and CD3+/TCR- jejunal IEL. RAG-1 was not expressed in colonic IEL. Thus, the epithelium of small intestine is a site for extrathymic T cell maturation in humans.
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10.
  • Madani, Hatef (författare)
  • Capacity-controlled Ground Source Heat Pump Systems for Swedish single-family dwellings
  • 2012
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The overall objective of this thesis is to develop a structured method to approach the challenge of better understanding the techniques and potential for capacity control in Ground Source Heat Pump (GSHP) systems used in Swedish single-family dwellings. This thesis aims at development of a generic model of the system that can be used for comparative, descriptive, and predictive analysis of capacity controlled GSHP systems in single-family dwellings.In order to develop the generic model, first, a conceptual model of the reality of interest is developed based on the objective of the model. Second, a quantitative model of the system is developed based on the conceptual model. Third, experimental studies are carried out in order to obtain better understanding of the behavior of the system and its components and also to validate the capabilities of the model. Furthermore, some examples are presented to show how the generic model developed and evaluated at the previous stages can be used to address the questions in the context of capacity control in GSHP systems.As the first example of applications of the generic model, a comparative analysis is made between the annual performance of on/off-controlled and variable-capacity GSHP systems. The results show that dimensioning of the on/off-controlled GSHP unit based on the peak heat demand of the building plays a significant role when the annual performance of the on/off controlled GSHP system is compared with that of the variable speed GSHP system. As the second example, another comparative analysis is performed, this time to compare three common methods whose purpose is to control on/off-controlled GSHP system. Based on the results from the detailed analysis of these three control methods, it is recommended not to use the constant hysteresis method to avoid large supply temperature oscillation or large deviation from the required temperatures.Finding a proper brine mass flow rate, either variable or constant, is a challenge when a variable capacity heat pump system (a heat pump system equipped with a variable speed compressor) is designed. Therefore, as the third example of applications of the generic model, analysis is performed on a variable-capacity GSHP system equipped with a variable speed compressor and variable speed pump in U-pipe borehole heat exchanger. The results show that a single speed liquid pump but with a very carefully-selected brine mass flow rate would be still an appropriate option for variable speed heat pump systems, if COP maximization is the main concern.Finally, as the fourth example, the performance of a run-around coil heat recovery system equipped with a variable capacity heat pump unit is evaluated over a year. The results show that by retrofitting a well-sized variable capacity heat pump unit to the system, there is a potential to increase the amount of heat provided by the recovery system by more than 70%.In addition to the examples shown, the systematic approach and the generic model used in the present study can be applied to improve other control techniques and strategies and find new opportunities which can lead to saving energy and money, reducing the greenhouse gas emissions, and gaining higher credibility for GSHPs in the market.
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11.
  • Öhman, Henrik, 1964- (författare)
  • Low temperature difference power systems and implications of multi-phase screw expanders in Organic Rankine Cycles
  • 2016
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • New and old data on screw expanders operating with 2-phase mixtures in the admission line has been combined to enable the first public correlation of adiabatic expansion efficiency as a function of entry vapour fraction. Although not yet perfected, these findings have enabled an entirely new approach to the design and optimisation of Organic Rankine Cycles, ORCs. By allowing a continuous variation of vapour fraction at expander entry optima for thermal efficiency, second law efficiency and cost efficiency can be found. Consequently one can also find maxima for power output in the same dimension.This research describes a means of adapting cycle characteristics to various heat sources by varying expander inlet conditions from pure liquid expansion, through mixed fluid and saturated gas expansion, to superheated gas. Thermodynamic analysis and comparison of the above optimisations were a challenge. As most terms of merit for power cycles have been developed for high temperature applications they are often simplified by assuming infinite heat sinks. In many cases they also require specific assumptions on e.g. pinch temperatures, saturation conditions, critical temperatures etc, making accurate systematic comparison between cycles difficult. As low temperature power cycles are more sensitive to the ‘finiteness’ of source and sink than those operating with high temperatures, a substantial need arises for an investigation on which term of merit to use.Along with an investigation on terms of merit, the definition of high level reversible reference also needed revision. Second law efficiency, in the form of exergy efficiency, turned out to be impractical and of little use. A numerical approach, based on a combination of first and second law, was developed. A theory and method for the above is described. Eventually low temperature power cycle test data was compiled systematically. Despite differences in fluid, cycle, temperature levels and power levels the data correlated well enough to allow for a generalised, rough correlation on which thermal efficiency to expect as a function of utilization of source and sink availability. The correlation on thermal efficiency was used to create a graphical method to pre-estimate key economic factors for low temperature site potential in a very simple manner. A major consequence from the findings of this thesis is the reduced dependency on unique choices of process fluid to match heat source characteristics. This development significantly simplifies industrial standardisation, and thereby potentially improves cost efficiency of commercial ORC power generators.
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12.
  • Ahl, Amanda, et al. (författare)
  • Balancing formal and informal success factors perceived by supply chain stakeholders : A study of woody biomass energy systems in Japan
  • 2018
  • Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 175, s. 50-59
  • Tidskriftsartikel (refereegranskat)abstract
    • Small-scale woody biomass energy systems have an inherent ability to aid in emissions reduction while stimulating local economies and, as collective energy systems, are strongly connected to supply chain design based on local conditions and stakeholder integration. Despite an abundance of forest area alongside the promotion of biomass in energy policies, however, woody biomass utilization still remains low in Japan. The woody biomass supply chain, considered as a socio-technical system, involves a complex, cross-sectoral stakeholder network in which inter-organizational dynamics necessitates well-organized management based on an understanding of formal factors such as technology, as well as informal factors such as social relations and culture. In this paper, success factor perceptions from across the woody biomass supply chain are investigated based on semi-structured interviews with four stakeholders in the Kyushu region of Japan. Identified success factors here are: 1) respect of values & traditions, 2) transportation infrastructure, 3) business model integration, 4) relationship & trust, 5) local vitalization and 6) biomass quality control. A convergence as well as divergence of perceptions are observed, involving both formal and informal dimensions. Aiming to balance perceptions and to enable long-term success of woody biomass in Japan, a series of policy implications are drawn, including cross-ministerial integration, knowledge building on wood logistics, forest certification, local coordinators, biomass quality control standards and a feed-in-tariff for heat. This paper suggests a new arena of policy-making based on the importance of considering both informal and formal dimensions in energy policy.
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13.
  • Andersson, Catrine, 1982- (författare)
  • Hundra år av tvåsamhet : Äktenskapet i svenska statliga utredningar 1909-2009
  • 2011
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The aim of the thesis is to study the concept of marriage and discursive constructions linked to marriage in Swedish policy documents, SOU, 1909-2009. Focusing on marriage as a formal institution, and on form, rather than content – marriage is considered one of several ways of regulating intimate relationships, and the analysis is thus centred on the intimate and erotic aspects of marriage as an institution. Using queer and sociological theories on late modern intimacy, state regulation and concepts of norms, theoretical tools which make possible exploring historical discursive shifts of heteronormativity and coupledom are developed. Policy documents (SOU) are analysed using discourse analysis inspired by archaeology and history of concepts. In three chapters, each covering a part of the period 1909-2009, the discursive landscape of state intervention in marital and other coupled relations is traced. Three themes emerge in this analysis. Firstly, a discursive movement can be seen, from marriage, as a morally superior form of relation, to family, as one of several more or less encouraged forms of relations. Secondly, in using the theoretical framework of heteronormativity, it is suggested that heteronormativity is reshaped in paradoxical ways. The seemingly non-heteronormative, gender neutral marriage law introduced in 2009 was built discursively on a concept of love used from the 1980s in these materials for motivating extended civil rights for homosexuals. It was, however, a logic of love based on difference and essentialised homosexual identity. A non-heteronormative law was thus introduced on a heteronormative discursive basis, enforcing extended norms of coupledom in the process. Thirdly, the question of what discursive role marriage plays in relation to society is explored. By enforcing differentiation between sexual and non-sexual, reproductive and non-reproductive, coupled and non-coupled relationships, social order is maintained. For one hundred years, despite major changes, coupledom is constant.
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14.
  • Anund Vogel, Jonas, 1981-, et al. (författare)
  • Co-Creation in Living Labs to Accelerate Innovation
  • 2020
  • Ingår i: Civil Engineering Research Journal. - Irvine California United States : Juniper Publishers. - 2575-8950. ; 10:1
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • Innovation in the construction sector occurs as stepwise reconfigurations of subsystems, but sometimes the effect of many systems coincides and there is so called radical change. Stepwise reconfigurations of individual systems such as windows, insulation, and heat recovery systems have made it possible to heat buildings with preheated inlet air instead of water radiators. Thus, making building more sustainable, cheaper and resource-efficient; the potential for radical change has been achieved. The question is then why not every new building uses preheated inlet air? The reason is not the lack of innovation or new technologies. It is rather connected to malfunctioning structures related to incentives, collaboration, testing, and validation, resulting in norms and standards that aim to reproduce existing technologies, preferring incremental innovations over radical ones.This article argues that testbeds and Living Labs are a way to work on complex, multi-stakeholder and urgent problems in a co-creative way. In these labs there are possibilities to test technologies, in systems, in real buildings and cities. There are possibilities to follow-up, measure and adjust; to live, study, work and develop. The Living Labs have the potential of making new technologies standard to use in the course of years instead of decades and thus minimize unnecessary use of resources linked to the construction and use of buildings. In addition, it will help to make technologies more user-friendly, considering user needs, wishes and experiences, thus contributing to the effectiveness of the technologies developed and tested.
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15.
  • Bagge, Ebba, et al. (författare)
  • Pattern of endocrine treatment for epithelial ovarian cancer in the Southeast medical region of Sweden: a population-based study
  • 2019
  • Ingår i: Acta Oncologica. - : TAYLOR & FRANCIS LTD. - 0284-186X .- 1651-226X. ; 58:3, s. 320-325
  • Tidskriftsartikel (refereegranskat)abstract
    • Aim of the study: Endocrine treatment (ET) is an alternative as salvage therapy in epithelial ovarian cancer (EOC) but the usage in routine care is unknown. We evaluated the treatment patterns and outcome of patients receiving ET for EOC in the Southeast medical region in Sweden.Method: Patients were identified through the population-based Southeast Quality Registry for gynaecological cancer. Inclusion criteria were: age 18 years, histologically verified EOC diagnosed 2000-2013, ET for 4 weeks. Coverage compared with the Swedish National Cancer Registry was 100%. Data extracted from medical records was collected by means of a study-specific Case Report Form. Last date of follow-up was February 1st, 2018. All statistics were descriptive.Results: Altogether 248 (18%) of 1414 patients were treated with ET. Most (49%) had received only one, and 34% two previous lines of chemotherapy. Time from last chemotherapy to ET was 4 months, range 0-55months. The reason for initiating ET was tumor progression (66%), chemotherapy related toxicity (29%) and maintenance (4%). Tamoxifen was prescribed in 94% of cases. Best response was partial (amp;lt; 5%) and stable disease (50%). No patient had a complete response. 194 (78%) patients received subsequent chemotherapy, of these 27% had 3-7 lines of chemotherapy. Duration of ET was a median 4 months (range 1-80 months). Median time from ET to subsequent chemotherapy was 5 months (range 0-79). The median overall survival was 45 months (range 9-173).Conclusion: In the Southeast region of Sweden, endocrine treatment for EOC was prescribed inconsistently and in various settings, usually initiated by a rising CA-125 level. Poorer documentation and irregular tumor response assessment were observed for endocrine treatment compared to chemotherapy.
  •  
16.
  • Bengtsson, Peder, 1968- (författare)
  • Apply heat pump systems in commercial household products to reduce environmental impact : How to halve the electricity consumption for a household dishwasher
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • In the household appliance industry, heat pump systems have been used for a long time in refrigerators and freezers to cool food, and the industry has driven the development of small, high-quality, low-price heat pump components. In the last few decades, heat pump systems have been introduced in other household appliances, with the express purpose of reducing electricity consumption. Heat pump tumble dryers have been on the market since 2000 and dominate the market today. A heat pump dishwasher was introduced on the market in 2014 and a heat pump washing machine in 2016. The purpose of adding a heat pump system in these three products was to decrease electricity consumption.Papers I and II used a methodology where transient simulation models were developed and used to increase knowledge about how to decrease electricity consumption for a tumble dryer and a dishwasher by adding a heat pump system. Papers II to V showed that a lower electricity consumption and lower global warming potential together with an energy-efficient drying method, where no humid air evacuates to the kitchen, give a heat pump dishwasher competitive advantages compared to any conventional dishwasher currently on the market. Using simulations, this dissertation concludes that a future commercial heat pump dishwasher, using R600a as a refrigerant, will reduce electricity consumption and total equivalent warming impact (TEWI) by 50% compared to the conventional dishwasher.The willingness from the customer chain to pay extra for this heat pump dishwasher is because of the decreases electricity consumption and the fact that no humid air evacuates to the kitchen. This willingness makes the heat pump dishwasher to a variant which have possibility to succeed on the future market.The challenge for the manufacturer is to develop and produce a high-quality heat pump dishwasher with low electricity consumption, predict future willingness to pay for it, and launch it on the market at the right moment with the right promotion in order to succeed.
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17.
  • Bäcklund, Katarina, 1982-, et al. (författare)
  • Building Occupants, Their Behavior and the Resulting Impact on Energy Use in Campus Buildings : A Literature Review with Focus on Smart Building Systems
  • 2023
  • Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 16:17, s. 6104-6104
  • Tidskriftsartikel (refereegranskat)abstract
    • In the light of global climate change and the current energy crisis, it is crucial to target sustainable energy use in all sectors. Buildings still remain one of the most energy-demanding sectors. Campus buildings and higher educational buildings are important to target due to their high and increasing energy demand. This building segment also represents a research gap, as mostly office or domestic buildings have been studied previously. In the quest for thermal comfort, a key stakeholder in building energy demand is the building occupant. It is therefore crucial to promote energy-aware behaviors. The building systems are another key factor to consider. As conventional building systems are replaced with smart building systems, the entire scenario is redrawn for how building occupants interact with the building and its systems. This study argues that behavior is evolving with the smartness of building systems. By means of a semi-systematic literature review, this study presents key findings from peer-reviewed research that deal with building occupant behavior, building systems and energy use in campus buildings. The literature review was an iterative process based on six predefined research questions. Two key results are presented: a graph of reported energy-saving potentials and a conceptual framework to evaluate building occupants impact on building energy use. Furthermore, based on the identified research gaps in the selected literature, areas for future research are proposed.
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18.
  • Bäcklund, Katarina, 1982-, et al. (författare)
  • In Search for Untapped Energy-Saving Potential in Green and Smart Higher Educational Buildings—An Empirical Case Study Involving the Building Occupants
  • 2023
  • Ingår i: Buildings. - : MDPI AG. - 2075-5309. ; 13:12
  • Tidskriftsartikel (refereegranskat)abstract
    • Energy-intense activities and the unpredictable and complex behavior of building occupants lead to an increase in building energy demand. It is, therefore, crucial to study underlying factors for building energy demand related to the users. Higher educational buildings are relevant to study for several reasons: they host the future workforce and citizens, they are predicted to increase in numbers, and they represent a building type less studied. Furthermore, green-rated buildings equipped with smart building systems also represent a research gap that is relevant to address since such a building design involves IoT-functionalities and digital features for the building occupants to interact with. There is also a conceivable risk that if the users know that the building is green-rated and technologically advanced, this may alter their perception of the building operation and thus their behavior. To study the relationship between building occupants and such green and smart educational structure, a survey was conducted in a Swedish higher educational building; as a result, 300 responses were collected and analyzed. The responses revealed that the building occupants act with energy awareness, and they are conscious about energy-saving behaviors. One building feature in particular was studied: the Digital Room Panels (DRPs). The DRP allows the building occupants to modify the indoor temperature and is, therefore, essential for thermal comfort. One key finding from the survey revealed that 70% of the building occupants did not know how the DRPs operate. This study argues that this result can be explained with a lack of communication and user friendliness. Inadequate interactions with building systems could also result in opportunities for energy saving might not be realized. The findings of this case study led to valuable recommendations and suggestions for future research endeavors.
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19.
  • Bäcklund, Katarina, 1982-, et al. (författare)
  • Showcasing a Digital Twin for Higher Educational Buildings : Developing the Concept Towards Human Centricity
  • 2024
  • Ingår i: Frontiers in Built Environment. - : Frontiers Media SA. - 2297-3362. ; 10
  • Tidskriftsartikel (refereegranskat)abstract
    • Digital twin technology is an emerging technology within the built environment. There are yet many unexplored opportunities to utilize digital twins for facilitating the transformation towards a climate neutral building stock while also meeting the expectations from the building occupants. This article presents a case study of a digital twin, developed for an existing commercial building stock of campus areas in Sweden. The overarching purpose of the digital twin is to support both building occupants and building operators. This twofold human-centric approach represents a novel approach for building digital twins. The digital twin is based on 3D scanning and together with geospatial data, a real-like navigational indoor environment is created. Three innovative features are presented; the building analysis module, the digital twin mobile application and the building operations module. The results show that the digital twin improves the building occupant’s experience by supporting navigation and providing access to room booking system via this dedicated interface. Building management is also benefited by the digital twin through easier access to building data aggregated into one platform and a state-of-the-art analysis tool for optimizing the use of indoor space. The digital twin holds future potential to achieve operational excellence by incorporating feedback mechanisms and utilizing Artificial Intelligence to enable intelligent fault detection and prevention.  Keywords: 
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20.
  • Bäcklund, Katarina, 1982-, et al. (författare)
  • Showcasing the First Steps Towards a Digital Twin for Campus Environments
  • 2022
  • Ingår i: 2022 BuildSim Nordic. - : EDP Sciences.
  • Konferensbidrag (refereegranskat)abstract
    • This paper presents a path towards the implementation of a Digital Twin for campus environments. The main purpose of the Digital Twin is to accomplish an advanced analytical tool, which supports building owners, building operators and building users to reach an improved performance of the building. Digital Twins is new to the building and the real estate industry, hence research within this field is scarce. This paper contributes to the research by providing a methodology to implement a Digital Twin of an existing building stock of campus areas in Sweden. The main results obtained so far are presented. They indicate that the potential of a Digital Twin expands beyond the aspects of a navigational digital 3D model, including a state-of-the-art app that is developed from the Digital Twin platform.  
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21.
  • Chen, Yang (författare)
  • Novel cycles using carbon dioxide as working fluid : new ways to utilize energy from low-grade heat sources
  • 2006
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This licentiate thesis proposes and analyzes three carbon dioxide novel cycles, namely: the carbon dioxide transcritical power cycle, the carbon dioxide Brayton cycle and the carbon dioxide cooling and power combined cycle. Due to the different characteristics of each cycle, the three cycles are suitable for different applications. The CO2 transcritical power cycle is suitable for harvesting energy from low-grade heat sources, near which a low temperature heat sink is accessible. The CO2 Brayton cycle is suitable for harvesting the energy from relatively high-grade heat sources when there is no low temperature heat sink available. The CO2 cooling and power combined cycle is suitable for applications, where both power and cooling are needed (e.g. automobile applications, in which the cycle can utilize the energy in the engine exhaust gasses to produce power and provide cooling/heating to the mobile compartment room at the same time). Several models have been developed using the software known as Engineering Equation Solver (EES)1 for both cycle analysis and computer aided heat exchanger design. Different cycle working conditions have been simulated and different working parameters’ influence on the cycle performance has been explained. In addition, Refprop 7.02 is used for calculating the working fluid properties and the CFD tool Femlab has been employed to investigate the particular phenomena influencing the heat exchanger performance.
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22.
  • Cowan, David, et al. (författare)
  • REFRIGERANT LEAKAGE AND CONTAINMENT - OVERVIEW OF THE ACTIVITIES OF THE IIR WORKING PARTY ON MITIGATION OF DIRECT EMISSIONS OF GREENHOUSE GASES IN REFRIGERATION
  • 2011
  • Ingår i: 23RD IIR INTERNATIONAL CONGRESS OF REFRIGERATION. - : INT INST REFRIGERATION. - 9782913149885 ; , s. 3833-
  • Konferensbidrag (refereegranskat)abstract
    • In recent years Global emissions due to leakage of F-Gases from refrigeration and air conditioning equipment have continued to increase as HCFC and CFC refrigerants are replaced by non-ozone depleting, but higher GWP, HFC refrigerants. Although lower GWP HFO and natural refrigerants such as CO2, ammonia and hydrocarbons are increasingly used in new system designs, the upward trend in the use of HFC refrigerant and consequent emissions are likely to continue for some years in the future. The environmental damage caused by direct emissions from escape of refrigerant can be 30% or more of the total environmental impact of a RAC system. However, effective mitigation measures can reduce this significantly, to the extent that the total equivalent warming impact (TEWI) of systems containing high GWP refrigerants can be similar to (or even lower than) systems containing lower GWP refrigerants. Mitigation measures can take several forms including legislative, fiscal, the use of alternative technologies and refrigerants, improvements in design and work practices and skills training. The IIR has set up a Working Party to research, collate and disseminate information on such mitigation measures. This will be made available via the FRIDOC database. The objectives and progress against these objectives are described in this paper.
  •  
23.
  • Friluftsliv explored : An environmental and outdoor teaching approach for knowledge, emotions and quality of life
  • 2021
  • Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
    • Friluftsliv explored doesn’t only include nature knowledge, techniques in the outdoors and outdoor pedagogics but also covers ecology, human ecology, geography, environmental and societal questions, history, health, biology, craft and lots of practical activities -both for urban and rural friluftsliv. In this translation to English of the revised fifth edition of the Swedish book there are many activities and the text is suitable for the modern day.Friluftsliv embraces the feeling around the campfire, paddling along winding rivers and walking towards the distant blue mountains. But, it is also to whittle a stick, to remember your waterproofs and to find your way home.Knowledge emerges when you combine imagination with facts and the glint in your eyes, using all our outdoor environments: forests, water, the coast, mountains and the nature close at hand.Emotion is to swim in crystal clear water far out in the archipelago and to see the clouds gliding across the sky. But also, to be able to present other sides of yourself, to be fascinated by your own body, the struggling ant and the sight of frost on trees.Quality of life is to experience friluftsliv – as it happens!
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24.
  • Lundqvist, Per, Professor, et al. (författare)
  • Global Efficiency of Heat Engines and Heat Pumps with Non-Linear Boundary Conditions
  • 2017
  • Ingår i: Entropy. - : MDPI. - 1099-4300. ; 19:8
  • Tidskriftsartikel (refereegranskat)abstract
    • Analysis of global energy efficiency of thermal systems is of practical importance for a number of reasons. Cycles and processes used in thermal systems exist in very different configurations, making comparison difficult if specific models are required to analyze specific thermal systems. Thermal systems with small temperature differences between a hot side and a cold side also suffer from difficulties due to heat transfer pinch point effects. Such pinch points are consequences of thermal systems design and must therefore be integrated in the global evaluation. In optimizing thermal systems, detailed entropy generation analysis is suitable to identify performance losses caused by cycle components. In plant analysis, a similar logic applies with the difference that the thermal system is then only a component, often industrially standardized. This article presents how a thermodynamic "black box" method for defining and comparing thermal efficiency of different size and types of heat engines can be extended to also compare heat pumps of different apparent magnitude and type. Impact of a non-linear boundary condition on reversible thermal efficiency is exemplified and a correlation of average real heat engine efficiencies is discussed in the light of linear and non-linear boundary conditions.
  •  
25.
  • Malakhatka, Elena, et al. (författare)
  • Actors’ Network Analysis and Bi-Directional Value Exchange Matrix Development for Living Labs: KTH Live-In-Lab Case Study
  • 2022
  • Ingår i: Smart Services Summit. - Cham : Springer. ; , s. 139-147
  • Bokkapitel (refereegranskat)abstract
    • In the scientific literature and in practice, quite a lot of attention is paidto the actors’ network analysis in living labs. Still, there is a lack of studies onvalue exchange between different actors in living laboratories. This study selectedthe distributed structure of the actors’ network in living lab since most European residential laboratories function according to this model. In the course of this exploratory study, we conducted two workshops: the first with participants from several European residential laboratories to discuss and co-design a framework for analyzingthe exchange of value between different stakeholders, and the second workshop—case study, where the proposed framework was applied on the actors network of the existed living laboratory—KTH Live-in-Lab. As a result, we got a detailed pictureof the network of actors and value exchange within the value co-creation model forKTH Live-in-Lab (Smart Home Services project).
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26.
  • Malakhatka, Elena, et al. (författare)
  • Co-Creating Service Concepts for the Built Environment Based on the End-User's Daily Activities Analysis : KTH Live-in-Lab Explorative Case Study
  • 2021
  • Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 13:4
  • Tidskriftsartikel (refereegranskat)abstract
    • The purpose of this study is to synthesize the widely used theories about co-creation from two main perspectives: co-creation as an innovation process and co-creation as a design process applied to the service concept design in the built environment context. The architecture, engineering, and construction (AEC) industry do not have much application of end-user-oriented service design in general, especially with intensive co-creation processes. To facilitate such a process, we are using a living lab environment as a laboratorial model of the real built environment, but with the opportunity to have access to the end-users and different types of stakeholders. Using the KTH Live-in-Lab explorative case study, we were able to discuss the concept of co-creation by distinguishing between co-creation as innovation and co-creation as a design process, facilitating the process of co-creation of service concepts for the proposed built environment including methods from both perspectives: innovation and design, and evaluating the process of service concepts co-creation for the built environment from the point of innovation, knowledge transfer, sustainability, and user experience.
  •  
27.
  • Malakhatka, Elena, et al. (författare)
  • End-user activities context information management framework for sustainable building operation
  • 2019
  • Ingår i: CISBAT 2019 | Climate Resilient Cities – Energy Efficiency & Renewables in the Digital Era4–6 September 2019, EPFL Lausanne, Switzerland. - : Institute of Physics Publishing (IOPP).
  • Konferensbidrag (refereegranskat)abstract
    • The concept of sustainable buildings includes not only technological aspects related to energy efficiency and resources usage optimization, but also aspects related to end-users' comfort, wellbeing, and everyday needs support. To understand the end-users' life activities in general and their preferences in particular, is necessary to enrich standard Building Management Systems (BMS) with human-generated and personal data. In this conceptual paper, we present an end-user context information management framework, which includes a reasoning layer, an acquisition layer, and a dissemination layer. The proposed framework is currently implemented in the KTH Live-in-Lab - a fully equipped testbed for research and innovation in the build environment.
  •  
28.
  • Malakhatka, Elena, 1989-, et al. (författare)
  • Identification of everyday food-related activities with potential for direct and indirect energy savings : KTH Live–in–Lab explorative case study
  • 2022
  • Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 163, s. 112792-112792
  • Tidskriftsartikel (refereegranskat)abstract
    • This exploratory study analyses the daily activities of the end-user in terms of assessing the potential for conserving direct and indirect energy. In the course of the study, a socio-technological system approach was applied, which made it possible to combine the methods of analysis and interaction of the social group (students) and technical infrastructure (living laboratory). The method of creating personas was also applied to segregate a large group of the population within one segment. This approach allowed us to consider in more detail the different types of behavior in the same segment. As a result, we got more personalized strategies for changing a behavior tailored for each individual persona. In conclusion, a recommendation was given on which policies implications and to which organizations to address.
  •  
29.
  • Malakhatka, Elena, et al. (författare)
  • Monitoring and Predicting Occupant's Sleep Quality by Using Wearable Device OURA Ring and Smart Building Sensors Data (Living Laboratory Case Study)
  • 2021
  • Ingår i: Buildings. - : MDPI AG. - 2075-5309. ; 11:10
  • Tidskriftsartikel (refereegranskat)abstract
    • Today's commercially-off-the-shelf (COST) wearable devices can unobtrusively capture several important parameters that may be used to measure the indoor comfort of building occupants, including ambient air temperature, relative humidity, skin temperature, perspiration rate, and heart rate. These data could be used not only for improving personal wellbeing, but for adjusting a better indoor environment condition. In this study, we have focused specifically on the sleeping phase. The main purpose of this work was to use the data from wearable devices and smart meters to improve the sleep quality of residents living at KTH Live-in-Lab. The wearable device we used was the OURA ring which specializes in sleep monitoring. In general, the data quality showed good potential for the modelling phase. For the modelling phase, we had to make some choices, such as the programming language and the AI algorithm, that was the best fit for our project. First, it aims to make personal physiological data related studies more transparent. Secondly, the tenants will have a better sleep quality in their everyday life if they have an accurate prediction of the sleeping scores and ability to adjust the built environment. Additionally, using knowledge about end users can help the building owners to design better building systems and services related to the end-user's wellbeing.
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30.
  • Molinari, Marco, et al. (författare)
  • Using living labs to tackle innovation bottlenecks: the KTH Live-In Lab case study
  • 2023
  • Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 338, s. 120877-120877
  • Tidskriftsartikel (refereegranskat)abstract
    • The adoption of innovation in the building sector is currently too slow for the ambitious sustainability goals thatour societies have agreed upon. Living labs are open innovation ecosystems in real-life environments usingiterative feedback processes throughout a lifecycle approach of an innovation to create sustainable impact. In thecontext of the built environment, such co-creative innovation and demonstration platforms are needed tofacilitate the adoption of innovative technologies and concepts for more energy-efficient and sustainablebuildings. However, their feasibility is not extensively proven. This paper illustrates the implementation anddemonstrates the feasibility of the Living Labs Triangle Framework for buildings living labs. This conceptualframework has been used to conceive the KTH Live-In Lab, a living lab for buildings. The goal of the Live-In Labwas to create a co-creative open platform for research and education bridging the gap between industry andacademia, featuring smart building demonstrators. The Living Lab Triangle Framework has been deployed tomeet the goals of the Live-in Lab, and the resulting concept is described. This paper then analyses the meth-odological and operational results introducing performance metrics to measure the economic sustainability, thepromotion of multidisciplinary research and development projects, dissemination and impact. The results arecompleted with a SWOT analysis identifying its current strengths and weaknesses. The results collected in thiswork fill a missing gap in the scientific literature on the performance of living labs and provide empirical evi-dence on the sustainability and impact of living labs.
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31.
  • Radestad, A. F., et al. (författare)
  • Long-term incidence of endometrial cancer after endometrial resection and ablation: A population based Swedish gynecologic cancer group (SweGCG) study
  • 2022
  • Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 0001-6349 .- 1600-0412. ; 101:8, s. 923-930
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction Minimally invasive methods to reduce menorrhagia were introduced in the 1980s and 1990s. Transcervical endometrial resection (TCRE) and endometrial ablation (EA) are two of the most frequently used methods. As none of them can guarantee a complete removal of the endometrium, there are concerns that the remaining endometrium may develop to endometrial cancer (EC) later in life. The primary aim was to analyze the long-term incidence of EC after TCRE and EA in a nationwide population. The secondary aim was to assess the two treatment modalities separately. Material and Methods The Swedish National Patient Registry and National Quality Registry for Gynecological Surgery were used for identification of women who had TCRE or EA performed between 1997-2017. The cohort was followed from the first TCRE or EA until hysterectomy, diagnosis of EC, or death. Follow-up data were retrieved from the National Cancer Registry and the National Death Registry. Expected incidence for EC in Swedish women was calculated using Swedish data retrieved from the NORDCAN project after having taken into account differences of age and follow-up time. Cumulative incidence of EC after TCRE and EA, was calculated. A standardized incidence ratio was calculated based on the expected and observed incidence, stratified by age and year of diagnosis. Results In total, 17 296 women (mean age 45.1 years) underwent TCRE (n = 8626) or EA (n = 8670). Excluded were 3121 who had a hysterectomy for benign causes during follow up. During a median follow-up time of 7.1 years (interquartile range 3.1-13.3 years) the numbers of EC were 25 (0.3%) after TCRE and 2 (0.02%) after EA, respectively. The observed incidence was significantly lower than expected (population-based estimate) after EA but not after TCRE, giving a standardized incidence ratio of 0.13 (95% confidence interval [CI] 0.03-0.53) after EA and 1.27 (95% CI 0.86-1.88) after TCRE. Median times to EC were 3.0 and 8.3 years after TCRE and EA, respectively. Conclusions There was a significant reduction of EC after EA, suggesting a protective effect, whereas endometrial resection showed an incidence within the expected rate.
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32.
  • Shahrooz, Mina, et al. (författare)
  • Effect of waste heat utilization on the performance of low temperature rankine cycle
  • 2020
  • Ingår i: Refrigeration Science and Technology. - : International Institute of Refrigeration. ; , s. 455-462
  • Konferensbidrag (refereegranskat)abstract
    • Low temperature Rankine cycle is a prominent solution for power generation in Waste Heat Recovery (WHR) application. The performance of this cycle is affected by various parameters including characteristics of the heat source, working fluid and constraints in the system. In cases where the heat source has a limited mass flux and therefore variable temperature, the amount of extracted heat affects the performance of the cycle including net power and efficiency which is also related to the working fluid. This is in the paper expressed in terms of a heat utilization factor, ?, which shows the ratio of extracted heat to the maximum possible extraction rate in the specific case. This factor affects the performance of the cycle by moving the pinch point location in the evaporator. Results indicate that this factor has great impact on the performance of the cycle and the effect varies for different working fluids. 
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33.
  • Shahrooz, Mina, et al. (författare)
  • Natural refrigerants for low temperature power cycles
  • 2018
  • Ingår i: Refrigeration Science and Technology. - : International Institute of Refrigeration. - 9782362150265 ; , s. 1373-1380
  • Konferensbidrag (refereegranskat)abstract
    • Working fluid selection determines various characteristics of low temperature Rankine cycles. Among other factors, the selected working fluid affects thermal performance, apparatus size and economic feasibility of the cycle. Beyond only affecting characteristics of the system, unrealistic preconditions for the working fluid of the system may force the designers in using environmentally harmful mixtures and force the outcome beyond boundaries of environmental regulations. There has been numerous research and scrutiny on various working fluids, but due to the unstructured and unorganized orientation of previous studies, there is no comprehensive insight on relationship of different characteristics of the working fluid and overall performance of the system. This work intends to develop a numerical evaluation approach, using a modified stochastic optimization algorithm as a search engine. The paper further explores and questions the existing criteria for optimization of working fluids in Rankine cycle. Rather than just finding the optimum fluids for different cases, this study aims to investigate the behavior of different fluids around optimum points and see the bigger picture to find trends in different fluid behaviors. Analysis of results show two main behaviors among the fluids in subcritical cycles. In the first type behavior, the optimum points for output work, thermal efficiency and exergy efficiency lie very close to each other, while in second type, these optimum points are not close. There is a transition from first type behavior to second type for a ratio of critical temperature around 0.9 of heat source inlet temperature. These results also show the importance of key performance parameter determination.
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34.
  • Shahrooz, Mina, et al. (författare)
  • Performance of binary zeotropic mixtures in organic Rankine cycles (ORCs)
  • 2022
  • Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 266, s. 115783-
  • Tidskriftsartikel (refereegranskat)abstract
    • Compared to pure fluids, zeotropic mixtures have the potential to lower the irreversibilities in low temperature Rankine cycles by better temperature profile matching of the working fluid with the heat source/sink. However, having a gliding temperature does not guarantee performance boost over pure fluids, as many factors influence the exergy efficiency of the cycle. In this study, 25 pure fluids and 104 binary mixtures of natural working fluids are analyzed in subcritical ORCs with heat source temperature range of 125-300 degrees C and different condensing conditions and the results are investigated within two frameworks: (1) comparing the mixtures to their pure constituents, (2) comparing the mixtures to the best performing pure fluid. In one behavior type, the performance of the mixture falls between the performance of its pure constituents for all evaporator pressure range, and the mixture provides no benefit. However, some mixtures could provide performance boost in a specific evaporator range. Therefore, the maximum allowable evaporator pressure plays an important role in the performance comparison of zeotropic mixtures to their pure constituents. Mixtures which outperform their pure constituents in the first perspective, are further analyzed in the second perspective. Finally, a screening method is presented to map the binary mixtures with performance boost compared to their pure constituents and high absolute exergy efficiency. This method is based on the key thermophysical properties of the fluids including critical temperature and normal boiling point, as well as working conditions such as heat source and heat sink temperature and PPTD in the evaporator and the condenser.
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35.
  • Svane, Örjan, et al. (författare)
  • Negotiated outcomes - Actor-oriented modelling of energy efficiency in a Stockholm city district renewal
  • 2012
  • Ingår i: Proceedings of the 6th Biennial Meeting of the International Environmental Modelling and Software Society. ; , s. 1768-1775
  • Konferensbidrag (refereegranskat)abstract
    • "What if the renewal of Rinkeby-Kista, Stockholm, were to make it part of a 2 kW Society?" Renewal of the city district's 25 000 flats from the 1970s is due and a network organisation, "Järva Boost" is established. A cross-disciplinary team of KTH researchers develop a computerised model to simulate energy efficiency gains resulting from actors' decisions. Inputs are measures that building owners, energy providers, residents, planners etc. might propose. They can be technical institutional or socio-cultural. Outputs are energy use in kW/person and CO2 emissions. To guide model development, an "ideal type" usage situation is outlined. The energy system is modelled "upstream" from end use, to identify larger efficiency potentials. The model interface is designed to enable the "staging" of actors' negotiations: The manager influences the properties of the climate shell, the residents the energy used for cooking, and the energy provider the primary energy mix. The concepts of "Household Activities System" and "Energy Usage Systems" give theoretical framework for modelling. The former conceptualises residents' activities, the latter the technology providing services to the activity. Simulations give contrasting outcomes: "business as usual" vs. "most favourable". Used in practice, simulations might simplify negotiations and coming to agreement.
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36.
  • Yang, Chen, 2011- (författare)
  • Thermodynamic Cycles using Carbon Dioxide as Working Fluid : CO2 transcritical power cycle study
  • 2011
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The interest in utilizing the energy in low‐grade heat sources and waste heat is increasing. There is an abundance of such heat sources, but their utilization today is insufficient, mainly due to the limitations of the conventional power cycles in such applications, such as low efficiency, bulky size or moisture at the expansion outlet (e.g. problems for turbine blades). Carbon dioxide (CO2) has been widely investigated for use as a working fluid in refrigeration cycles, because it has no ozonedepleting potential (ODP) and low global warming potential (GWP). It is also inexpensive, non‐explosive, non‐flammable and abundant in nature. At the same time, CO2 has advantages in use as a working fluid in low‐grade heat resource recovery and energy conversion from waste heat, mainly because it can create a better matching to the heat source temperature profile in the supercritical region to reduce the irreversibility during the heating process. Nevertheless, the research in such applications is very limited. This study investigates the potential of using carbon dioxide as a working fluid in power cycles for low‐grade heat source/waste heat recovery. At the beginning of this study, basic CO2 power cycles, namely carbon dioxide transcritical power cycle, carbon dioxide Brayton cycle and carbon dioxide cooling and power combined cycle were simulated and studied to see their potential in different applications (e.g. low‐grade heat source applications, automobile applications and heat and power cogeneration applications). For the applications in automobile industries, low pressure drop on the engine’s exhaust gas side is crucial to not reducing the engine’s performance. Therefore, a heat exchanger with low‐pressure drop on the secondary side (i.e. the gas side) was also designed, simulated and tested with water and engine exhaust gases at the early stage of the study (Appendix 2). The study subsequently focused mainly on carbon dioxide transcritical power cycle, which has a wide range of applications. The performance of the carbon dioxide transcritical power cycle has been simulated and compared with the other most commonly employed power cycles in lowgrade heat source utilizations, i.e. the Organic Rankin Cycle (ORC). Furthermore, the annual performance of the carbon dioxide transcritical power cycle in utilizing the low‐grade heat source (i.e. solar) has also been simulated and analyzed with dynamic simulation in this work. Last but not least, the matching of the temperature profiles in the heat exchangers for CO2 and its influence on the cycle performance have also been discussed. Second law thermodynamic analyses of the carbon dioxide transcritical power systems have been completed. The simulation models have been mainly developed in the software known as Engineering Equation Solver (EES)1 for both cycle analyses and computer‐aided heat exchanger designs. The model has also been connected to TRNSYS for dynamic system annual performance simulations. In addition, Refprop 7.02 is used for calculating the working fluid properties, and the CFD tool (COMSOL) 3 has been employed to investigate the particular phenomena influencing the heat exchanger performance.
  •  
37.
  • Zanki Alujevic, Vlasta (författare)
  • Energy use and environmental impact from hotels on Adriatic Coast in Croatia : current status and future possibilities for HVAC systems
  • 2006
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This thesis analyses a specific type of energy usage system, “energy usage in hotels”, and how this system behaves. In order to evaluate the current state of energy use in hotels, an energy audit questionnaire was developed and conducted among 31,5% of hotels on the Adriatic coast. The energy audit was used as a tool to set a benchmark for energy consumption in hotels and to identify opportunities for increased energy efficiency measures in HVAC systems. The analysis has shown that the average energy consumption in hotels on the Adriatic coast is in the range of 159 to 180 kWh/m2 and 162 to 225 kWh/m2 for seasonal and non seasonal hotels respectively. In order to establish a relationship between different independent variables in the hotels (total floor area and number of rooms) and dependent variables, such as electricity and oil consumption, mathematical statistical methods, such as correlation and regression analysis, were implemented. The objective of this thesis was also to develop - from an energy, environmental and economical points of view - a methodology for the design and retrofit of HVAC systems in the hotels on the Adriatic coast. The methodology named HOTECO is based on a system thinking approach. With respect to the technological aspects, the first step was to analyse conventional HVAC system designs and to compare it with the three most promising alternative HVAC systems utilizing renewable energy sources for a typical hotel. Computer modelling in TRNSYS was used to assess energy consumption. TRNSYS software has been used for simulations for a number of years, is internationally recognized, and has been validated and verified. It was concluded that energy and environmental savings in hotels on the Adriatic coast could be achieved using readily available technologies. The HOTECO methodology also demonstrated a framework that supports decision making iv regarding system selection and operational strategies to limit environmental impact from HVAC systems in hotels. Four scenarios for energy consumption in hotels on the Adriatic coast with regards to current state of energy systems and improved retrofit solutions utilizing renewable energy source were given.
  •  
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